James mckechnie and habtley blyth pratt



J. McKECHNIE AND H. B. PRATT. AEROSTAT STRUCTURE OF mean AIRSHIPS. APPUCATIGN FILM) MAR. 25, EH9,

1,308,291 Patented July 1, 1919.

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JAMES MICKECHNIE AND HARTLEY BLYTH PRATT, or nannow-m-rumtnss,

ENGLAND, Accra-Janus 'm vicisnns LIMITED, or WESTMINSTER, tonnonfl ENGLAND.

AEROSTAT STRUCTURE OF RIGID Almsnirs.

Specification oi. Letters Patent.

Patented July 1,1919.

Annlication filed March 25. 1919. Serial No. min

To airman i may concern lie it known that we, Sir JAMES,MC- we 7* r Immune, 1\.. 'B, P1,, and l'lAR'ILEY BLYTH l m'rrfboth subjects of the King of Great Britain. residing at Naval Construction 'Nliorks. l arrow-in-Furncss; in the c'o'unty of Lancaster, England, have invented certain new and useful Improvements in or 'Relatin to the Aerostat Structure of Rigid Airshipsjoif winch the. following s a specifica- This invention relates to the aerostat structure of rigid airships of the kind in which tubular flexible members are employed. inflated under pressure to give the desired rigidity, and has for its chicf ob ject to provide the necessary strength and rigidity with" a minimum weight of material.

According to this invention, the aerostat structure comprises a girder structure formed of aseries of iniiatable'iiexible tubes jointed. together at their ends.

A long tube, Whether of rigid or flexible material, inflated with gas under pressure, resists compression or bending loads as long as the longitudinal tension stress in the material due-to the internal pressure is sufficient to maintain the whole of the tube material in tension when subjected to the said loads. The tubular girders of the framework are of fabric or other flexible material having the necessary tensile strength and the tubes are inflated with air or other gas compressed sufficiently to insure resistance to the compression, bending or other loads to which they may be subjected as part of an aerostat structure.

The framework may be substantially similar in general arrangement to the framework of the present type of rigid airship, that is, itmay comprise longitudinal irders, transverse frames of polygonal s ape built of a series of shorter similar girders, external diagonal wires between the joints of the longitudinal and transverse girders, transverse wiring to fix the shape of the transverse frames and suspension wiring to suspend the weights from the transverse frames.

In order that the said invention may be clearly understood and readily carried into effect we will describe the same was with, reference to the aecoinpalnyiiigf'dra'hgings, in which Figuresl and 2 are viewsat r1" htf ii ngljds to each other showing thegenera'far'r. e-

'ment of part of an aerost bodying this invention, and (U My I Figs. 3 and a are detail views, at right I i a; t striicture exh- V ,n r;

angles to each other, of the connections between the hollow girder ends. v if.

A is the girder tube provided ends with the conical metal caps a on whiohlthey are wired at a. B, B are the exte rha'ldiagonal wires, B, B the transverse'lwiring and B B the suspension wiring. G, C are the joint members to which the girder ends are secured. r

The tubes A are preferably woven seamless and the fabric proofediwitli 'rnbber or other air proof composition. It may (be of single or multiple ply linen or cotton or may be woven of metallic wire. As shown especially at the right hand side of Fig. 4 the tubes terminate in the truncated conical end pieces a preferably pressed from sheet metal and provided with the cylindrical part a 'strengthened at the edge by the lip (1 the end of the tube fabric extending over the part a? and being wired firmly on so as to provide a gas tight joint. Inflation of the tube to the desired pressure is provided for by a non-return valve of any suitable type fitted to the cap or end piece/a.

To connect up the ends of the inflatable girders to form the aerostat structure the joint member C is provided with connecting lugs c at each side, four pairs of lugs being shown in Fig. 4 to connect up four girder ends. The conical tube ends a are provided with corresponding lugs a and bolts 0, 0 connect the parts together and form at one end a hinge which allows of angular adjustmcnt of the girders around the connecting member. Diagonal wires B, as shown especially in Fig. 1, are carried between the connecting members C of adjacent transverse frames each formed by a. set of short tubular girders A arranged to form a polygon by the aid of the radial transverse Wires B which connect up the members C of each frame to a central point. The diagonal Wires B cross each other as shown in Fig. 1 between the transmit the pressure of the gas bags to the tubular girders. The general construction is analo ous to that commonly employed, with such modifications as are necessary to adapt the construction to the inflated girder structure.

The internal pressure required to 've the necessary rigidity can readily be ca culated for an airship of given dimensions; 20 lbs. per 5 uare inch may be taken as an approximafte re for an airshi of moderate size. The tu es may be provided with pressure gafges to show the pressure to which they are ated.

\Vhat we claim and desire to secure by Letters Patent of the United States is 1. An aerostat structure for rigid airships, comprising a girder construction formed of inflatable flexible tubes attached at their ends to adjoining members to form transverse frames connected together by longitucinal tubular girders, for the purpose speci- An aerostat structure for airshi s comprising a girder construction forme of influted tubes attached at their ends to adjoining members, to form transverse frames connected by longitudinal inflated tubes.

3. An aerostat structure for rigid airships comprising a irder construction formed of inflated fiexib e tubes attached at their ends to adjoining members, by means of metal end pieces or caps, to form transverse frames connected by longitudinal inflated tubular girders;

4. An aerostat structure for rigid airships comprising a irder construction formed of inflated fiexib e tubes attached at their ends to adjoining inflated flexibl tubes by means of metal end pieces or caps to form transverse frames connected by longitudinal inflated tubular 'rders, said frames provided with radial an dia one] wire stays.

5. An aerostat s ructure for rigid airships comprising a girder construct-ion formed of a number of inflatable flexible tubes hinged at their ends through connecting members, to form a series of transverse frames interconnected by girders and provided with radial diagonal Wire stays.

JAMES MCKECHNIE. HARTLEY BLYTH PRATT. 

